linux-kernel - [PATCH 4.19 173/191] ext4: fix leaking sysfs kobject after failed mount

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Message-Id: <20201103203248.773799962@linuxfoundation.org>
Date:   Tue,  3 Nov 2020 21:37:45 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        syzbot+9f864abad79fae7c17e1@...kaller.appspotmail.com,
        Eric Biggers <ebiggers@...gle.com>, Jan Kara <jack@...e.cz>,
        Theodore Tso <tytso@....edu>
Subject: [PATCH 4.19 173/191] ext4: fix leaking sysfs kobject after failed mount

From: Eric Biggers <ebiggers@...gle.com>

commit cb8d53d2c97369029cc638c9274ac7be0a316c75 upstream.

ext4_unregister_sysfs() only deletes the kobject.  The reference to it
needs to be put separately, like ext4_put_super() does.

This addresses the syzbot report
"memory leak in kobject_set_name_vargs (3)"
(https://syzkaller.appspot.com/bug?extid=9f864abad79fae7c17e1).

Reported-by: syzbot+9f864abad79fae7c17e1@...kaller.appspotmail.com
Fixes: 72ba74508b28 ("ext4: release sysfs kobject when failing to enable quotas on mount")
Cc: stable@...r.kernel.org
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
Link: https://lore.kernel.org/r/20200922162456.93657-1-ebiggers@kernel.org
Reviewed-by: Jan Kara <jack@...e.cz>
Signed-off-by: Theodore Ts'o <tytso@....edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/ext4/super.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4594,6 +4594,7 @@ cantfind_ext4:
 
 failed_mount8:
 	ext4_unregister_sysfs(sb);
+	kobject_put(&sbi->s_kobj);
 failed_mount7:
 	ext4_unregister_li_request(sb);
 failed_mount6: